Why do I get an OutOfMemoryError when JBoss starts?
If you see an OutOfMemoryError during startup of JBoss, it may be due to a bug in your JVM http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6373059. Shortly after the "Core System Initialized" log message, JBoss attempts to unzip and deploy its deployment files. Since (in version 4.0.2 at least) it does so without regard to what is actually a zip file, it exposes a bug in certain JVM versions. The problem is in how the JVM deals with unzipping files.
Caused by: java.lang.OutOfMemoryError
at java.util.zip.ZipFile.open(Native Method)
According to Sun's release notes, this problem is fixed in v1.5.0_08 http://java.sun.com/j2se/1.5.0/ReleaseNotes.html.